The present invention relates generally to the field of drill bits for core boring and more particularly to a rotating dry drilling bit for low thrust boring operations in very remote locations.
Core boring or “diamond drilling” is well known in the fields of geophysics, mineral and hydrocarbon exploration. Generally a drill bit is attached to the end of a rotating string. The drill bit comprises a bit crown with cutting blades including abrasive elements, such as natural and/or synthetic diamonds, impregnated therein. The know art discloses a variety of core drill bits for high thrust drilling operations such as is necessary to penetrate thick rock layers. The friction generated by high thrust drilling also necessitates the use of drilling mud to lubricate and cool the drill bit. U.S. Pat. No. 4,760,888 “Drill Bit for Core Boring” issued to Saito on Aug. 2, 1988 and U.S. Pat. 6,474,425 “Asymmetric Diamond Impregnated Drill Bit” issued to Truax et al on Nov. 5, 2002 are exemplary. These drill bits are robust and well suited to high thrust drilling and coring operations that are land based or extend from a deep see drilling rig and obtain core samples that are meters long and centimeters in diameter.
However, with the advent of extreme depth submarine and remote extra-terrestrial exploration, high thrust drilling is not practical because of the weight restrictions that such exploration entails and the impracticality of using a lubricating and cooling fluid. Drilling equipment for submarine and extra-terrestrial must be small and light for transportation and therefore low powered. Such low powered drilling equipment is unable to utilize the large scale heavy drill bits used in terrestrial drilling applications.
Therefore there is a need for a coring drill bit that is able to be used dry in low thrust drilling in extremely remote locations.